Suction device



Sept; 12, 1939.

MH, cAULr-'IELD SUCTION DEVICE Filed July 8, 1937 Patented Sept. 12,19139 UNITED VSTATES PATENT OFFICE 10 Claims.

In the use of pipettes and similar devices for transferring orcollecting liquids, it is customary to draw the liquid into the tubewith suction created by mouth. This practice involves a delinite hazardin the possibility of drawing the liquid, which may be of an injuriousnature, into the mouth, and many serious and even fatal accidents haveoccurred from this cause. In the larger types of pipette from which thecontained liquid may empty by gravity, this method of drawing the liquidinto the tube has the further disadvantage of being diincult to controlfor accurate measurement of the liquid due to the necessity, after theliquid is drawn in, for sealing the end of the tube in order to preventthe liquid from discharging, this operation requiring withdrawal of thetube from the mouth and a consequent momentary interruption of thesuction so that the finger may be placed over the end of the tube.

One object of the present invention is to provide an evacuating orsuction device suitable for use with pipettes, and adapted in principlefor many other useful purposes, that will entirely eliminate theaforesaid hazard.

Another object is to provide a device of the stated character that shallbe capable of close manual control under the continuous observation ofthe operator so that volumetric measurements may be accomplished withaccuracy and rapidity.

Another object of the invention is to provide a device of the characterdescribed that `shall be .simple and practicable in form and operation,and that may be manufactured at relatively low expense.

The invention resides further in certain structural details andarrangements of parts hereinafter described and illustrated 'in theattached drawing, wherein:

Figure l is a vertical sectional view of a preferred embodiment of theinvention in its application to a conventional type of pipette;

Fig. 2 is a top plan View of the device, and

Fig. 3 is a sectional view illustrating a modication Within the scope ofthe invention.

With reference to Figs. 1 and 2 of the drawing, the embodiment of theinvention therein disclosed comprises a bulb I of rubber or similarresilient material having an opening in each end. In one of theseopenings is secured a nipple 2 in which is mounted a Valve 3 and of thetype, for example, conventionally employed in pneumatic tires. The valve3, which is normally held closed by spring pressure in the conventionalmanner is arranged in the nipple so that it may open against the springunder the effect of fluid pressure exerted from the bulb side, butsuction within the bulb acts with the spring to hold the valve closed. Arod 4 extends through the bulb and through the opening 5 at the oppositeside of the 5 bulb, and projects slightly beyond the mouth of saidopening, the inner end of this rod being guided in an element 6 threadedinto the end of the nipple 2. The inner extremity of the rod 4 isprovided with a button 'I which engages the end l0 of the valve stem andwhich prevents retraction of the valve rod 4 from the element 6.Pressure on the outer projecting end of the rod has the effect ofopening the valve 3.

It will now be apparent that if the bulb I is col- 15 lapsed and thecontained air discharged, through the opening 5 for example, and ifsubsequently the opening 5 is closed and the rod 4 depressed by placinga nger over the opening and the collapsing pressure then released topermit the bulb 20 to assume its normal shape, the resulting suctionwill be impressed upon the passage through the nipple 2, and, the valvebeing open, air will then be drawn through the nipple to the interior ofthe bulb, 25

As shown in the drawing, the bulb I with its nipple 2 is supported in aframe 8 which has at one end an arm 9 with an aperture embracing thenipple IG at the one end of the bulb through which the aperture 5extends. At the opposite 30 end of the frame 8 is a hollow boss II whichis internally threaded at the inner side o f the yoke for reception o fthe correspondingly threaded end o fthe nipple 2, and on the outer sideof the boss is threaded a sleeve I2 which supports an inner sleeve I3 ofresilient rubber. This innerY sleeve lis adapted to receive the end of apipette I4 and to form a sealed joint between the pipette and the frame.In the present instance, the pipette is graduated as shown. 40

In the operation of this device, the outer attenuated end of the pipetteIII is immersed in the usual manner in the liquid to be drawn into thepipette. Thereafter, the rubber bulb I is collapsed by pressure of thefingers, the air es-V caping through the aperture 5. While the bulb isin the collapsed state, the finger is then placed over the opening 5 toseal the latter, the rod 4 at the same time being depressed by pressureof the finger and the valve 3 thereby opened. TheAl pressure on the bulbI is then released and the resulting expansion of the bulb creates asuction on the tube I4 which draws the liquid into the latter. The riseof the liquid in the tube is clearly Visible to the operator, and whensuflicient liquid has entered the tube, as indicated by the graduations,the iiow may be stopped by removal of the nger from the opening 5, whichpermits the valve to close and admits air to the interior of the bulbthrough the opening 5. If it be desired to permit a portion of theliquid taken into the tube to escape, this may be accomplished bydepression of the valve rod 4 while maintaining the iinger tip in suchposition that the opening 5 of the bulb is not sealed. Under theseconditions, the liquid will iiow by gravity from the tube. Thisdischarge of liquid from the tube may be accelerated by completelysealing the opening 5 with the nger and exerting pressure on the bulb tocollapse the latter whereby the air in the bulb is forced downwardlyinto the top of the pipette. All of these operations are capable ofclose control, with the movements of the liquid in the tube entirelyvisible to the operator, so tnat extremely accurate regulation of theflow either into or from the pipette is afforded. With a graduated tubeof the character illustrated, accurate measurements of liquid may bemade with great facility. If prior to taking up the liquid in the tubeI4 it be desired to agitate the body of liquid from which the withdrawalis made, this may be accomplished efficiently and rapidly by expellingthe air from the bulb I downwardly through the tube and into the saidbody. It is apparent that all of the hazards previously eX- perienced inthe use of pipettes, wherein the suction is eiected by mouth, iseliminated by this device, and that, further, a more accurate and rapidmeasurement of the liquid in the tube can be obtained.

In Fig. 3, I have illustrated a modification within the scope of theinvention. Since in this embodiment the elements of the assembly areessentially the same as those of the embodiment illustrated in Figs. 1and 2 and previously described, the principal parts are designated bythe same reference numerals. In this embodiment, the position of thevalve 3 in the nipple 2 is reversed, so that iiuid pressure applied tothe nipple through the medium of the bulb I is not effective to open thevalve, whereas the valve will open under suction exerted by expansion ofthe bulb, assuming, of course, that the opening 5 at the top of the bulbis closed. In this case, the frame 8 is formed with a passage I5 whicheX- tends from the interior of the hollow boss I I at a pointintermediate the valve 3 and the inner end of the tube I4, to the outerend of the frame. The outer end of the passage I5 is controlled by avalve I6 of a type, for example, similar to the valve 3 previouslydescribed, the valve I6 being arranged so that it will remain closedunder all normal working conditions, and may be opened only by pressureexerted upon the projecting end I'I of the valve stem.

In the operation of this device, liquid may be drawn into the tube I4 byrst collapsing the bulb I, thereafter placing the nger over the opening5 to seal the latter, and then releasing the bulb to permit expansion,the resulting suction opening the valve 3 and being imposed upon thetube I4. The resulting flow of liquid upwardly into the tube I4 may beinterrupted at the will of the operator either by removing the nger fromthe opening 5 or by opening the valve I6 by pressure of a linger uponthe projecting end of the valve stem. Normally, interruption of theinward flow of liquid into the tube I4 will be effected by simplyuncovering the opening 5 of the bulb. If now it be desired to dischargeall or a portion of the liquid from the tube I4, this may beaccomplished by opening the valve I'I to admit air to the interior ofthe boss I I and to the upper or inner end of the tube I4.

I have found it of advantage to locate the valve, as in the embodimentof Fig. l, at the inner end of the bulbI or closely adjoining the mouthof the pipette, rather than at the outer end of the bulb, since by thismeans the cut-oi action of the valve with respect to the pipette is morerapid. By this means lag in operation is avoided and the column orfliquid in the pipette is maintained substantially without change as ofthe moment the valve is closed. Accurate measurement of the liquid isthus facilitated. Somewhat the same eiTect is obtained in the embodimentof Fig. 3 by extending the passage I5 to a point closely adjoining theinner end of the pipette. I have found it of advantage also to employ aspringpressed valve of the general character described, instead of avalve of the ball type, for example, as it is essential for maximumoperating efficiency that the valve action be definitely positive.

The aforedescribed device, while of high utility in conjunction withpipettes, may find other useful applications where evacuation of fluidfrom a tube or container is required, and there are to be no impliedlimitations in this respect. It is apparent, also, that the device maybe considerably modied as to details without departure from theprinciple of the invention.

I claim:

1. In a device of the stated character, the combination with a resilientbulb having a pair of openings, one of said openings being adapted formanual control, a normally closed valve for controlling the other ofsaid openings, and a valve rod operatively associated with said valveand extending in the interior of the bulb to the firstnamed opening,whereby the act of manually sealing said opening may actuate the rod toopen the valve, the end of said rod being arranged with respect to saidopening to permit the opening of the valve by pressure on said rod whileleaving said opening unsealed whereby to aiord an unobstructed ilow ofair through the bulb.

2. In a device of the stated character, the combination with a resilientbulb having aligned openings respectively at opposite sides of saidbulb, a normally closed valve controlling one of said openings, and avalve-actuating rod extending from the other of said openings to thevalve and constituting a means for manually opening said valve.

3. In a device of the character described, the combination With asuction bulb having a pair of openings, one of said openings beingadapted for manual control, of a valve controlling the other of saidopenings, a spring exerting pressure to close said valve, and meansextending to a point adjacent the first-named opening for manuallyopening said valve against the spring pressure and providing forcoordinated accurate control of said valve and opening.

4. In a device of the character described, the combination with asuction bulb having a pair of openings, one of said openings beingadapted for manual control, of a valve controlling the other of saidopenings, a spring exerting pressure to close said valve, andmanually-operated means for opening said valve against the pressure ofsaid spring.

5. In a device of the character described, the combination with asuction bulb having a pair of openings, one of said openings beingadapted for manual control, of a check valve controlling the other ofsaid openings, said valve being arranged to permit discharge of fluidthro-ugh said opening from the bulb and normally preventing flow throughsaid port in the opposite direction, `and manually-actuated means foropening said valve to permit the passage of fluid through said openingto the bulb.

6. The combination with a tube and a suction bulb attached to one end ofsaid tube and constituting a means for drawing a liquid by suction intothe other end of said tube, said bulb having a port for admission anddischarge of air independently of the tube and adapted for manualcontrol, a check valve controlling the connection between the bulb andthe tube and arranged to admit air to the bulb from the tube whilepreventing ow of air in the opposite direction, and manually-actuatedmeans for admitting air to the tube for subsequent gravity dischargefrom the latter of said liquid.

7. The combination with a tube and a suction bulb attached to one end ofsaid tube and constituting a means for drawing a liquid by suction intothe other end of said tube, said bulb having a port for admission anddischarge of air independently of the tube and adapted for Inanualcontrol, a check valve controlling the connection between the bulb andthe tube and arranged to admit air to the bulb from the tube whilepreventing iow of air in the opposite direction, vent means foradmitting air to the tube for effecting subsequent discharge of saidliquid from the tube, a normally closed valve controlling said vent, andmanually-actuated means for opening said valve.

8. The combination with a tube and a suction bulb attached to one end ofsaid tube and constituting a means for drawing a liquid by suction intothe other end of said tube, said bulb having a port for admission anddischarge of air independently of the tube and adapted for manualcontrol, a check valve controlling the connection between the bulb andthe tube and arranged to admit air to the bulb from the tube whilepreventing ow of air in the-opposite direction, a. spring exertingpressure to close said valve and said valve being adapted to be openedagainst the spring pressure by suction of the bulb, andmanually-actuated means for admitting air to the tube to eiectsubsequent discharge from the latter of said liquid.

9. The combination with a tube and a suction bulk attached to one end ofsaid tube and constituting a means for drawing a liquid by suction intothe other end of said tube, said bulb having a manually-controllableport for admission and discharge of air independently of the tube, meansnormally operative when said port is uncovered to seal the tube from thebulb, and manually-actuated means for admitting air to the tube to eiectsubsequent discharge from the latter of said liquid.

10. The combination with a tube and a suction bulb attached to one endof said tube and constituting a means for drawing a liquid by suctioninto the other end of said tube, said bulb having a port for admissionand discharge of air independently of the tube and adapted for manualcontrol, a valve controlling the connection between the bulb and thetube, a spring to normally close said valve, and manually-actuated meansfor opening said valve against the spring pressure.

MERVILLE H. CAULFIELD.

